1. Field of the Invention
The invention relates to a sun shield which can be moved between an operating position under a translucent roof area and a rest position next to this roof area, especially for an at least partially transparent motor vehicle roof with a shade tarp which is located underneath the roof and which is wound onto a take-up roller.
2. Description of Related Art
Shades of the initially mentioned type are used as anti-glare devices or to cover glass surfaces in a motor vehicle in various configurations. Thus, for example, published German Patent Application DE 42 10 972 A1 describes a shade as an anti-glare device with a pivotally mounted take-up roller for a roll-up hanging with a fall rod located on its pull out-side end, and with a drive device for the take-up roller. The hanging is guided when at least one telescoping rod is extended and engages the fall rod of the hanging. Such a shade is especially suited for the rear window of a motor vehicle, but less for a glass roof under which it must be pulled out roughly horizontally. For pulling-out horizontally, an additional support or guide for preventing excessive deflection is necessary.
Published German Patent Application DE 198 60 826 A1 describes a sun shield for a translucent roof area, especially a glass motor vehicle roof. The sun shield comprises a shade with a take-up roller, which, on its free edge, bears a clamping strip which runs in a self-locking manner in lateral slide guides, and which strip is engaged by tension belts which are guided via a deflection roller and which are connected to the take-up roller to transfer torque. The shade and the tension belts are kept tensioned by a spring arrangement. In order to keep the shade tensioned at any time and to prevent the formation of folds, in this known arrangement, the construction cost is relatively great.
A sun-shielding shade without guide rails for a motor vehicle is known from published German Patent Application DE 100 40 624 A1. The shade tarp is either itself relatively stiff or is carried on its front edge using guided guide rods or slide rods to prevent sagging. Its front or back edge is held in contact with the pertinent window.
Finally, German Patent DE 101 22 570 C1 and its counterpart published U.S. patent application US 2003/000630 discloses a sun-shielding shade for a motor vehicle roof which has a shade tarp which can be wound onto a take-up roller and which is located underneath the roof, with opposing side edges which are movably guided in the direction of shade movement on guide rails and are held in the transverse direction with pre-tensioning of the shade tarp.
In general, when the known shade arrangements are installed the installation tolerances are often low and can lead to undesirable formation of folds in the extended sun-shielding shade. This can be the case especially when the take-up roller and the transverse bow of the extended sun-shielding shade are not flush with one another.